Continuous casting method, and device therefor

ABSTRACT

A continuous casting method, and a device for use in the casting method, are disclosed. The flow state of the discharged molten metal is properly controlled, and thus, the amounts of residual non-metallic inclusions and gas bubbles within the molten metal are decreased, so that continuously cast slabs of a good quality can be produced. The continuous casting device includes a mould with a submerged nozzle installed therein, the submerged nozzle having a pair of discharge holes directed toward narrow faces of the mould. Further, an electromagnetic brake ruler is included for establishing a magnetic field within the mould. The electromagnetic brake ruler includes a base frame surrounding the mould, and iron cores projecting from near the wide faces of the mould, while the iron cores are wound with induction coils. It further includes a pair of electromagnetic transferring parts connected to the iron cores, and disposed immediately above the discharge holes of the submerged nozzle toward narrow faces of the mould and in parallel with a discharge direction of the molten metal. With the magnetic field applied within the mould, the separation capability for the non-metallic inclusions and gas bubbles is increased so as to greatly reduce the internal defects of the cast products.

FIELD OF THE INVENTION

The present invention relates to a continuous casting method, and adevice for use in the casting method. More specifically, the presentinvention relates to a continuous casting method, and a device for usein the casting method, in which the flow state of the discharged moltenmetal is properly controlled, and thus, the amounts of residualnon-metallic inclusions and gas bubbles within the molten metal aredecreased, so that continuously cast slabs of a good quality can beproduced.

BACKGROUND OF THE INVENTION

The molten metal continuous casting method has been adopted over thewhole world since 1960s. This method has various advantages comparedwith the general ingot making method, and therefore, it is utilized fora considerable part of the manufactured steel.

The quality of a continuously cast metal is classified into a surfacequality and an internal quality, and these qualities are closely relatedto the flow of molten metal within the mould.

FIGS. 1a and 1 b illustrate a mould used in the general continuouscasting method. Referring to these drawings, a molten metal is suppliedinto a mould 10 through a submerged nozzle 11 which has two dischargeholes 11 a. The molten metal which is discharged from the two dischargeholes forms jet flows toward a narrow face 13, and the jet flow collideswith the narrow face 13 to be divided into an ascending flow U and adescending flow D. That is, the jet flow is divided into fourrecirculating streams U1, U2, D1 and D2. In FIG. 1b, reference code Sindicates a turning point of the recirculating streams.

The molten metal which is introduced into the mold contains non-metallicinclusions (also called “inclusions” below) such as Al₂O₃, MnO, SiO₂ andthe like which have been formed in the pre-treating stage or have comefrom the refractory materials. The molten metal further includes inertgas bubbles (also called “gas bubbles” below) which have been injectedinto the submerged nozzle 11, for preventing the clogging of the nozzle11. The gas bubbles have sizes of several scores of microns to severalmillimeters. The inclusions and gas bubbles which are contained in theupper recirculating streams have a density lower than that of the moltenmetal. Therefore, they are subjected to a floating force in a directionopposite from gravity, and therefore, they move in the combined vectordirection of the molten metal flow and the floating force. Then theygradually move toward the meniscus of the molten metal, to be capturedby the mold flux 14.

However, the inclusions and gas bubbles which are contained in the lowerrecirculating streams D pass through the jet flow region near the nozzledischarge holes 11 a before moving toward the upper recirculatingstreams U. The velocity of the jet flow is faster than the ascendingvelocity due to the floating force, and therefore, the inclusions andthe gas bubbles rarely pass through the jet flow. Accordingly, theinclusions and the gas bubbles which are contained in the lowerrecirculating streams cannot reach the meniscus of the molten metal, butcontinuously circulate along with the lower recirculating streams.Therefore, they are likely to remain within the cast metal.Particularly, in the case of the continuous curved caster, the particlescontained in the lower recirculating streams spirally move due to theinfluence of the floating force to be ultimately adhered on thesolidified layer, i.e., on the upper layer of the cast piece, therebyforming an inclusion/gas bubble accumulated region in the upper layer ofthe cast piece.

When the cast piece is subjected to a rolling, the residual inclusionsand gas bubbles are exposed to the surface, thus causing surfacedefects. Or they remain within the cast piece, and when an annealing iscarried out, the gas bubbles expand to cause internal defects.

In order to solve this problem and to improve the quality of the castpiece, conventionally the discharge angle Θ of the submerged nozzle isproperly adjusted, so as to improve the quality of the cast piece. Thedischarge angle Θ of the submerged nozzle gives a great influence to theflow of the molten metal.

If the discharge angle Θ is increased, the amount of the descending flowincreases, while that of the ascending flow decreases. As a result, thevelocity of the molten metal on the meniscus of the melt is slowed, sothat a stable surface of the melt is maintained. Therefore, theworkability is improved, and the initial solidification is stablycarried out, thereby upgrading the surface quality of the cast piece.However, if the discharge angle Θ is increased, large amounts ofinclusions and gas bubbles are buried deeply into the cast piece,because they lose the opportunity of floating to the meniscus of themelt. Thus the internal quality of the cast piece is aggravated.

On the other hand, if the discharge angle Θ is decreased, the amount ofthe descending flow decreases, and therefore, the defects due to theinclusions and the gas bubbles may decrease. However, if the dischargeangle is decreased, the amount of the ascending flow increases, and thevelocity of the molten metal at the meniscus of the melt steeplyincreases. Therefore, the surface quality of the cast piece is decreaseddue to the entrainment of the mould flux at the melt surface, and due tothe formation of vortex. These problems become much more serious as thecasting speed becomes faster.

Thus, if only the submerged nozzle is employed, a limit in controllingthe flow of the molten is confronted. Therefore, as shown in FIG. 2a, anelectromagnetic brake ruler (EMBR) 20 is installed immediately below thedischarge hole 11 a of the submerged nozzle. Thus the Lorentz forcebased on a magnetic field and a flow is utilized to decrease the flowvelocity. (This is proposed in Swedish Patent SE 8,003,695, and U.S.Pat. No. 4,495,984.)

The method of FIG. 2a has been put to the practical use, but it is notused at present because flow distortions occur in the direction ofevading the flow resistance of the magnetic field, rather thandecreasing the flow velocity by the magnetic field.

In order to overcome this problem, the magnetic field is horizontallydistributed over the entire width of the mould as shown in FIGS. 2b and2 c. (Swedish Patent SE 9,100,184, U.S. Pat. No. 5,404,933, and JapanesePatent Application Laid-open No. Hei-2-284750). However, the distortionphenomenon has been observed in these methods all the same.

When a dc magnetic field is not applied, the molten metal which has beendischarged from the discharge holes 11 a of the submerged nozzle 11forms flow fields as shown in FIG. 3a. However, if the magnetic field isapplied over the entire width of the mould, the flow steams are formedas shown in FIG. 3b. That is, compared with the case where there ismagnetic field, the jet flow is markedly spread in the thicknessdirection of the mould. Therefore, the average velocity of the jet flowdirected toward the mould narrow face is slowed.

As the velocity of the jet flow is slowed, the inclusions and the gasbubbles of several scores to several hundreds of microns have a long wayto travel from the descending flow region to the ascending flow region,compared with the case where a magnetic field is not applied.

Meanwhile, most of the inert gas which has been injected through thenozzle into the molten metal has of several millimeters, and floats frombetween the narrow faces to the meniscus of the melt (the floatingdistance depends on the molten metal injection speed and on the amountof the injected gas, and this distance corresponds from near thedischarge hole to the narrow face in the case where the minimum gasamount is injected, while it corresponds from immediately above thedischarge hole to the narrow face in the case where the maximum gasamount is injected). If the velocity of the main flow is light, thedirection of the main flow is not greatly affected by the floating ofthe inert gas bubbles. However, if the average velocity of the main flowis decreased by applying a magnetic field, the direction of the mainflow is greatly influenced by the floating force of the inert gas. Themain flow is raised toward the surface of the melt by the floating forceof the inert gas and by the flow resistance of the magnetic field whichis established immediately below the submerged nozzle. When theinfluence by the floating force of the inert gas decreases, the flow islowered in the casting direction to draw an S curve as shown in FIG. 3b(this is called “non-solidified rising molten metal flow adjacent to thesubmerged nozzle”). Thus the flow collides with the mould narrow racewith a large angle.

When the jet flow is cleaved by colliding with the narrow face of themould, the flow amounts of the cleaved flows are decided by thecolliding angle. For example, if a perpendicular collision occurs, theupper and lower cleaved flows are same in their flow amounts. However,if the colliding angle is lowered, the amount of the lower flow isincreased. Under this condition, the ratio of the amount of the lowerflow to that of the upper flow is decided by the casting speed, thenozzle discharge angle, the injected amount of the inert gas, and themagnetic field strength. However, at the general working conditions, theratio is about 6:4, if a magnetic Field is not applied. If a magneticfield is applied over the entire width, the ratio becomes 8:2.Therefore, if a magnetic field is applied like in the conventionalmethod, the amount of the lower flow increases, while the amount of theupper flow decreases. Accordingly, the velocity of the molten metaldecreases immediately below the melt meniscus, and the height differenceof the melt meniscus also decreases. Thus the melt face is stabilized,so as to improve the surface quality.

However, due to the increase in the amount of the lower flow, largeamounts of inclusions and gas bubbles are contained in the recirculatingflow. Therefore, if a magnetic field is applied over the entire width,the increase of the floating opportunity owing to the decrease of theaverage velocity is offset. Therefore, the improvement of the internalquality cannot be expected due to the fact that the inclusions and thefine inert gas bubbles are not removed.

SUMMARY OF THE INVENTION

In order to solve the above described problems, the present inventorscarried out theoretical studies and simulating experiments. Based onthese studies and research, the present inventors came to propose thepresent invention.

Therefore it is an object of the present invention to provide acontinuous casting method, in which an induced dc magnetic field isapplied in parallel with the molten metal discharge direction, and thus,the residual amounts of inert gas bubbles and non-metallic inclusionssuch as Al₂O₃, MnO and the like are minimized, thereby improving theinternal quality of the cast pieces.

It is another object of the present invention to provide a continuouscasting device which is used for the above continuous casting method.

In achieving the above objects, the continuous casting method accordingto the present invention includes the steps of: feeding a molten metalthrough discharge holes of a submerged nozzle into a mould; andestablishing a magnetic field on the incoming molten metal,characterized in that a main flux part of the magnetic field isdistributed from immediately above the discharge holes of the submergednozzle in parallel with a discharge direction of the molten metal.

In another aspect of the present invention, the continuous castingdevice according to the present invention includes: a mould with asubmerged nozzle installed therein, the submerged nozzle having a pairof discharge holes directed toward narrow faces of the mould; and anelectromagnetic brake ruler for establishing a magnetic field within themould, and the electromagnetic brake ruler includes: a base framesurrounding the mould; iron cores projecting from near wide faces of themould and with induction coils wound thereon; and a pair ofelectromagnetic transferring parts connected to the iron cores, keepinga certain distance from the wide faces of the mould, and disposedimmediately above the discharge holes of the submerged nozzle towardnarrow faces of the mould and in parallel with the discharge directionof the molten metal.

Further, the device of the present invention further includes a meansfor controlling a non-solidified rising molten metal flow near thesubmerged nozzle.

BRIEF DESCRIPTION OF THE DRAWINGS

The above objects and other advantages of the present invention willbecome more apparent by describing in detail the preferred embodiment ofthe present invention with reference to the attached drawings in which:

FIG. 1 illustrates the flow of the molten metal within the generalmould, with FIG. 1a being a plan view, and FIG. 1b being a sidesectional view;

FIGS. 2a, 2 b and 2 c illustrate the constitutions of the conventionalcontinuous casting devices, with various electromagnetic brake rulersbeing installed thereon;

FIGS. 3a and 3 b illustrate the molten metal flow within the mould inaccordance with the presence or absence of the conventionalelectromagnetic brake ruler;

FIG. 4 illustrates the constitution of the continuous casting deviceaccording to the present invention, with FIG. 4a being a plan view, FIG.4b being a side sectional view, and FIG. 4c being a perspective view ofthe critical portion;

FIG. 5 illustrates the constitution of another embodiment of thecontinuous casting device according to the present invention, with FIG.5a being a side sectional view, and FIG. 5b being a perspective view ofthe critical portion;

FIG. 6 is a side sectional view of the continuous casting device inwhich the electromagnetic transferring parts of the second embodimentare added;

FIG. 7 illustrates the flow of the discharged molten metal within themould of the present invention; and

FIGS. 8a and 8 b comparatively illustrate the molten metal flows fordifferent embodiments of the continuous casting device according to thepresent invention.

DETAILED DESCRIPTION OF THE INVENTION

Basically in the present invention, a proper magnetic field isestablished from immediately above discharge holes of a submerged nozzlewithin a mould, in parallel with the molten metal discharge direction.

FIG. 4 illustrates the constitution of a first embodiment of thecontinuous casting device according to the present invention, with FIG.4a being a plan view, and FIG. 4b being a side sectional view.

The continuous casting device according to the present inventionincludes: a submerged nozzle 11 with a pair of discharge holes 11 aformed therein; a mould 10 with the submerged nozzle installed therein,the discharge holes 11 a being directed toward narrow faces 13 of themould 10; and an electromagnetic brake ruler 40 for establishing aninduced magnetic field within the mould 10.

The major feature of the continuous casting device according to thepresent invention is the electromagnetic brake ruler. FIG. 4cillustrates in detail the electromagnetic brake ruler (EMBR).

As shown in FIG. 4c, the electromagnetic brake ruler 40 of the presentinvention includes: a base frame 43 surrounding the mould 10; iron cores44 projecting from near wide faces 12 of the mould; and a pair ofelectromagnetic transferring parts 41 and 42 connected to the iron cores44 and keeping a certain distance from the wide faces 12 of the mould10.

The base frame 43 may be formed integrally with the iron cores 44. Or itmay be formed separately from the iron cores in such a manner that itmay be moved in the direction of the wide faces. In the latter case, theinduction coils 45 can be easily wound.

The iron cores 44 are wound with the induction coils 45, and therefore,they may induce induction currents in the mould.

Further, the pair of electromagnetic transferring parts 41 and 42 areconnected to the iron cores 44, keeping a certain distance from the widefaces of the mould, and thus supplies an induced dc magnetic field tothe mould. The electromagnetic transferring parts 41 and 42 of thepresent invention are disposed starting from immediately above thedischarge holes 11 a of the submerged nozzle toward the narrow faces 13of the mould and in parallel with the molten metal discharge directions.That is, the electromagnetic transferring parts 41 and 42 of theelectromagnetic brake ruler 40 should be disposed in parallel with thedischarge directions of the molten metal. The electromagnetictransferring parts 41 and 42 serve the role of changing the distributioncontour of the magnetic field of the iron cores, before transferring thefield to the mould. Therefore, they do not have to consist of a singlepiece, but may be a plurality of pieces.

The electromagnetic brake ruler 40 is a means for controlling the risingflow of the non-solidified molten metal near the submerged nozzle. Thestructure of the ruler 40 may be made different depending on thedischarge angle of the molten metal. The discharge angle Θ of thedischarge holes may be inclined downward at angle of 1 to 90 degrees.The electromagnetic transferring parts 41 and 42 should be disposed inparallel with the discharge direction of the molten metal even in thecase where the discharge angle Θ is varied.

Meanwhile, in the electromagnetic brake ruler 40, as shown in FIG. 4b,the electromagnetic transferring parts 41 and 42 may extend up to thenarrow face 13 of the mould. However, it is important that the parts 41and 42 should cover the region immediately above the molten metal jetnearest to the submerged nozzle (or the region where floating of theinert gas is brisk). In the region immediately above the molten metaljet, the floating of the inert gas is most brisk. Therefore, in thisregion, numerous gas bubbles can be observed, and the size of thisregion depends on the casting speed and the injection amount of theinert gas. Under the usual conditions, the mentioned region ispositioned between the submerged nozzle and the narrow face. In the casewhere the electromagnetic brake ruler 40 covers the area immediatelyabove the molten metal jet, the constitutions of the base frame 53, theiron core 54 and the induction coil 55 are as shown in FIG. 5b, and aresimilar to those of FIG. 4c. However, the transferring parts 51 and 52become short so as to cover only the region immediately above the moltenmetal jet.

That is, the electromagnetic brake ruler 40 should cover the regionimmediately above the molten metal jet nearest to the submerged nozzleat least, and should extend up to the narrow face of the mould at most.

Now the continuous casting method using the above described apparatuswill be described.

Generally, if a conductive material moves across magnetic fluxes, thenelectric currents are induced in the conductive material. Owing to theinteraction between the induced electric currents and the magneticfield, the Lorentz force is generated, which acts in a directionopposite to the motion of the conductive material, and is proportionalto the multiplication of the moving velocity of the conductive materialby the square of the applied magnetic field strength. The Lorentz forcereduces the velocity of the flow, alters the direction of the flow, orcleaves the flow into a plurality of streams. Accordingly, if a magneticfield is properly applied over a flow, then the flow velocity and theflow direction can be properly altered.

The present invention is based on this principle. That is, during acontinuous casting of a metal, the residual inclusions and gas bubblesare minimized, so that the internal quality problem of the cast productis improved. However, the method of the present invention has anessential difference from the conventional methods as described below.

That is, if the residual inclusions and gas bubbles within the castproduct are to be minimized, the inclusions and gas bubbles should becontained in the upper layer of the recirculating stream to the maximum.That is, they have to be made to float.

For this, the following conditions have to be satisfied.

First, the velocity of the jet flows discharged from the discharge holeshas to be slowed before the jet flow is divided into an ascending flowand a descending flow. Thus, a sufficient time has to be secured so thatthe inclusions and gas bubbles contained in the descending flow canfloat toward the surface of the ascending flow.

Second, the flow direction has to be controlled so that the collisionangle of the jet flow of the molten metal at the narrow face would notbe lowered. Thus the amount of the ascending flow has to be madegreater, so that the greater part of the inclusions and gas bubbles willbe contained in the ascending flow.

For this purpose, in the continuous casting devices of FIGS. 4 and 5,magnetic fluxes are applied in parallel with the discharge direction ofthe molten metal jet.

That is, if the magnetic field is distributed in parallel with thedischarge direction of the molten metal jet, then the jet flow becomesas shown in FIG. 7. Consequently, the plan view of the jet flow patternbecomes as shown in the upper portion of FIG. 3b, while its frontal viewis as shown in the lower portion of FIG. 3a. Thus the overall moltenmetal flow is slowed. Therefore, in the present invention, the flow isspread in the thickness direction of the mould as well as being slowed,so that the time for floating of the inclusions and gas bubbles can besufficiently secured. At the same time, at the portion A of FIG. 4bwhere the floating force acts, the rising of the flow is inhibited bythe flow resistance owing to the magnetic field applied above the flow.Further, the flow direction is made not to be distorted, and thecolliding angle (at the narrow face) is sufficiently secured, so thatthe amount of the descending flow would not increase.

Thus the inclusions and gas bubbles contained in the descending flow areminimized.

Meanwhile, the colliding angle of the molten metal becomes differentdepending on the discharge angle at the submerged nozzle, the length ofthe applied magnetic field, and its field strength. If the collidingangle becomes unnecessarily upward, the flow velocity on the meltsurface becomes too fast. Therefore, the floating time has to bedesigned such that the maximal floating can be realized with the minimalascending flow amount.

The length of the electromagnetic brake ruler 40 should be such that itshould extend from the molten metal discharge point to the narrow faceat the maximum. The variation of the flow of the molten metal inaccordance with the length of the magnetic field is illustrated in FIG.8.

That is, FIG. 8a illustrates a case where a brisk floating occurs in aregion corresponding to ¼ of the length from the discharge hole 11 a tothe narrow face. That is, the electromagnetic brake ruler 40 covers onlythis region (immediately above the molten metal jet). FIG. 8billustrates a case where the ruler 40 is extended up to the narrow face.In both of the drawings, the flow patterns of the discharged moltenmetal are illustrated. It is seen that in both of the cases, the flowpatterns are almost the same. This owes to the fact that the majority ofthe inert gas floats from near the discharge hole to the melt surface,and that the floating of the inert gas slightly pushes up the moltenmetal flow. However, it is seen that the magnetic field cannot give anygreat influence to the flow of the molten metal near the narrow face.

Accordingly, if the upward biasing of the flow is inhibited at theregion where the floating is brisk, then the overall flow pattern of themolten metal will become the same in both of the above mentioned cases.Further, near the narrow face remote from the brisk floating region, themolten metal has been spread in the thickness direction of the mould,and has been slowed. Therefore, the Lorentz force become negligible inthis area. Consequently, it is important that the electromagnetic brakeruler 40 should cover at least the region where the floating of theinert gas is brisk. Outside this region, the distribution of themagnetic field is not very important. Therefore, a plurality of piecesof the electromagnetic transferring parts may be provided as shown inFIG. 6 in such as manner that the inhibited non-solidified molten metalflow is not destroyed, and that the pieces should extend up to thenarrow face outside the brisk region. In this manner, fine adjustmentsof the flow near the narrow face are possible. FIG. 6 illustrates a casewhere the electromagnetic transferring parts with a varied angle aredisposed near the narrow face outside the brisk floating region, so thatthe colliding angle can be adjusted slightly upward, in a state wherethe non-solidified rising molten metal flow is inhibited. FIG. 6 alsoillustrates a case where the electromagnetic transferring parts areadded below the flow near the narrow face so as to reduce the velocityof the descending flow. In order to carry out fine adjustments near thenarrow face, the electromagnetic transferring parts of various shapesmay be added near the narrow face.

When carrying out the continuous casting using the above describedcasting device, about 35-40% of discharged amount of the molten metalcan be made to ascend.

Here, the magnetic flux density of the electromagnetic brake ruler 40should be preferably 1000-6000 Gausses. If the applied flux density isless than 1000 Gausses, the altering of the flow becomes insufficient,while if it exceeds 6000 Gausses, any more altering of the flow cannotbe expected.

Now the present invention will be described based on experimentalexamples.

Comparative Example 1

Like in the general casting conditions, a molten metal discharge rate of2.6 tons/min was adopted, and the downward discharge angle was adjustedto 0-25 degrees. With a magnetic field not applied, a computer-aidedsimulating experiment was carried out. Thus a comparison was madebetween the upper recirculating stream and the lower recirculatingstream to measure the number of the inclusions and gas bubbles.

In the case where a magnetic field was not applied, 35-40% of thedischarged molten metal was formed into an ascending flow, the restforming a descending flow. The time for the discharged jet flow to reachthe narrow face was about 0.55-1 second. Thus about 70% of theinclusions and gas bubbles was contained in the upper recirculatingstream, while the rest is contained in the lower recirculating stream.

Comparative Example 2

At conditions the same as those of the comparative example 1, a magneticfield was applied as shown in FIG. 2b to carry out a computer-aidedsimulating experiment. Then a comparison was made between the upperrecirculating stream and the lower recirculating stream to measure theinclusions and gas bubbles.

In this case, only about 10-20% of the discharged molten metal wasformed into an ascending flow, and about 34% of the inclusions and gasbubbles were floated to the upper recirculating stream, while theremaining 66% was contained in the lower recirculating stream. The timefor the discharge jet flow to reach the narrow face was about 1.4-3seconds in average.

From the above results, it is seen that it was worse than the case wherea magnetic field was not applied. This corresponds to the actual factorycircumstance.

Inventive Example

At conditions the same as those of the comparative example 1, a magneticfield was applied as shown in FIG. 4b. Then a computer-aided simulatingexperiment was carried out, and then, a comparison was carried outbetween the upper recirculating stream and the lower recirculatingstream to measure the inclusions and gas bubbles. Here, the flux densityof the applied magnetic field was varied within the range of 1000-6000Gausses.

In this inventive example, about 35-40% of the discharged molten metalwas formed into an ascending flow. The time for the discharged jet flowto reach the narrow face was about 1.4-3 seconds in average. Further,about 93% of the inclusions and gas bubbles were floated to the upperrecirculating stream, while only 9% of them remained in the lowerrecirculating stream. Thus the separation of the inclusions and gasbubbles was much superior.

According to the present invention as described above, the separationcapability for the non-metallic inclusions and the gas bubbles isimproved. Therefore, the internal defects of the cast piece due to thenon-metallic inclusions and the gas bubbles are markedly diminished.

What is claimed is:
 1. A continuous casting method comprising the stepsof: feeding a molten metal through discharge holes of a submerged nozzleinto a mould; and establishing a magnetic field on the molten metal thusfed, characterized in that a main flux part of the said magnetic fieldis distributed from immediately above said discharge holes of saidsubmerged nozzle in parallel with discharge direction of the moltenmetal, wherein 35-40% of the molten metal thus discharged is made toascend by the magnetic field.
 2. The continuous casting method asclaimed in claim 1, wherein the magnetic field thus applied has a fluxdensity of 1000-6000 Gausses.
 3. A continuous casting device comprising:a mould with a submerged nozzle installed therein, said submerged nozzlehaving a pair of discharge holes directed toward narrow faces of saidmould; and an electromagnetic brake ruler for establishing a magneticfield within said mould, said electromagnetic brake ruler comprising: abase frame surrounding said mould; iron cores projecting from near widefaces of said mould and with induction coils wound thereon; and a pairof electromagnetic transferring parts connected to said iron cores,keeping a certain distance from said wide faces of said mould, anddisposed immediately above said discharge holes of said submerged nozzletoward narrow faces of said mould and in parallel with a dischargedirection of the molten metal.
 4. A continuous casting devicecomprising: a control means for controlling a non-solidified ascendingmolten metal flow near said submerged nozzle, wherein said control meanscomprises at least a pair of electromagnetic transferring parts forapplying magnetic fields; said electromagnetic transferring parts areconnected to iron cores disposed in parallel with a molten jet flowdirection near said discharge hole of said submerged nozzle; and saidelectromagnetic transferring parts establish main magnetic fluxesperpendicular to a flow of the molten metal and perpendicular to adrawing direction of cast strands.
 5. The continuous casting device asclaimed in claim 4, wherein said electromagnetic transferring partscover a region immediately above the molten metal jet nearest to saidsubmerged nozzle.
 6. The continuous casting device as claimed in claim5, wherein said electromagnetic transferring parts have an arbitraryshape at a region where a floating of inert gas is not brisk, that is,outside a region immediately above the molten metal jet nearest saidsubmerged nozzle.
 7. The continuous casting device as claimed in claim5, wherein the magnetic field has a flux density of 1000-6000 Gausses.8. The continuous casting device as claimed in claim 4, wherein disposedangles of said electromagnetic transferring parts are varied within arange of 1 to 90 degrees, so as to make them parallel with the moltenmetal jet flow near said submerged nozzle.
 9. The continuous castingdevice as claimed in claim 4, wherein said control means has anoperation range falling between said discharge holes and said narrowfaces.